The current practice of routine x-ray examination of dentally asymptomatic adults contributes significantly to the radiation and economic burden of the U.S. population. This practice does not appear to be based on a scientific assessment of the utility of radiologic technology. This study is designed to assess the efficacy of x-ray examinations in the evaluation of dentally asymptomatic adults. The specific aims are: to determine the total prevalence of positive findings from dental radiographs; to determine the sensitivity and specificity of dental radiographic projections (bite-wing, periapical and panoramic) independently and in various combinations; to determine the yield of important pathological findings associated with specific clinical indicators; to develop and test selection criteria for dental x-ray examinations; to determine the utility of recommending x-ray examinations at frequent intervals; and, to assess the potential effects of selection criteria on radiation thrift and expenditure savings. The methods for the study will consist of three parts. In the first part, we will analyze a unique data set which is part of the VA Dental Longitudinal Study in Boston and which contains bite-wing, periapical and panoramic radiographs taken on 1221 volunteer subjects every three years since 1968. We will determine prevalence of total positive radiographic findings, and the sensitivity and specificity of each type and various combinations of projections. In the second part we will develop and test selection criteria for dental radiography using the VA data set and identify clinical indicators which are associated with positive radiographic findings. We will use this VA data set to evaluate the incidence of new significant positive radiographic findings which are discovered every three years. In the third part, we will assess the utilization of dental radiographic examinations in three practice settings: an H.M.O., a neighborhood health center, and a dental group practice. Using the selection criteria developed from the VA data set, we will then prospectively evaluate the effect of a continuing education program and the institution of a requisition form in these settings. Policy recommendations for the clinical use of dental x-ray examinations will be designed so as to minimize cost and radiation exposure while maintaining the necessary diagnostic information.